Finding inflection point on a x,y plot

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jchris14 2015-11-10

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评论： Matt J 2015-11-11

Hi, how can i find the inflection point of the plot in the circled area. See attached image. The plot is based on x,y coordinates rather than a function.

Thanks

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Image Analyst 2015-11-10

Do you mean the x location where the "flat-ish" part in the black oval goes from concave down to concave up? Just curious, since this could be imprecise and happen anywhere over a wide range of x, why do you want this location?

jchris14 2015-11-10

well yes. But is there a way to find the exact points from either the plot or the x,y data?

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Adam Barber 2015-11-10

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Do you have an analytic (symbolic) representation of the function? Or just numerical data?

If you have an analytic representation, you can just differentiate it twice to find the inflection point. You can also do this numerically with gradient or diff, then find where it is zero (or approximately zero) to find the inflection point.